Sometimes portions of an aircraft's flight route may become unavailable due to disruptions such as, for example, convective weather conditions or air traffic congestion. In the event a portion of the flight route becomes unavailable, an alternative route that avoids the blocked airspace needs to be determined. Specifically, the aircraft should be re-routed along the alternative route, and directed to the final destination as quickly and as effectively as possible.
Two known and commonly used approaches for determining the alternative route are re-routing on a waypoint based network and re-routing on a uniform grid based network. The waypoint based network approach may be a relatively simple way to determine the alternative route. However, the waypoint network, as historically defined, includes a limited set of waypoints, which in turn translates into a limited set of re-routing options for the aircraft. This in turn often results in a longer detour than necessary around the blocked airspace. Re-routing on a uniform grid network typically includes a network of connected points uniformly spaced throughout the airspace and is often based on the center or edge points of a grid of polygons, such as, for example, hexagons, rectangles, or triangles. Determining the alternative route based on the uniform grid network is often inefficient as well, depending on the granularity of the grid as well as the approach used to form connections between the points.
In addition to the above mentioned difficulties, a route determined based on the uniform grid network may also be inoperable, depending on how the path of the route aligns with the airspace sectors' geometries. Specifically, the aircraft may fly too closely to an edge of a sector, or may even cut a corner of a sector. This should be avoided because of the extra workload created for air traffic controllers when the aircraft flies too closely to an edge of a sector, or cuts a corner of a sector. Accordingly, there exists a need in the art for an improved approach for determining an alternative route for an aircraft.